1. Field of the Invention
The present invention relates to a display apparatus, and more particularly, to a field sequential display apparatus that reduces color breakup and a method thereof.
2. Description of the Related Art
A liquid crystal display apparatus commonly includes upper and lower substrates, a liquid crystal panel composed of a liquid crystal between the upper and lower substrates, a driving circuit which drives the liquid crystal panel, and a backlight unit which provides white light to the liquid crystal.
Methods of operating the liquid crystal display apparatus can be classified into RGB (red, green, blue) color filter methods and color field sequential drive methods.
In a liquid crystal display apparatus using the RGB color filter method, each pixel is divided into RGB unit pixels, RGB color filters are respectively provided in the RGB unit pixels, and light is transferred to the RGB color filters through the liquid crystal by the backlight unit, thereby forming a color image.
In a liquid crystal display apparatus using the color field sequential drive method, RGB light sources are arranged in each pixel instead of decomposing the pixel into RGB unit pixels, and light of the three primary colors R, G, and B is sequentially transferred from the RGB backlight to each pixel through the liquid crystal in a time division manner, thereby displaying a color image using an afterimage effect.
FIG. 1 shows a basic method of driving a backlight of a field sequential display apparatus according to the related art.
Referring to FIG. 1, one image field is divided into RGB sub-fields to be displayed on a screen. Data R is first displayed on a liquid crystal panel, a light source R is turned on after the liquid crystal responses completely, light source R is then turned off to display data G on the liquid panel, a light source G is turned on after the liquid crystal responses completely, light source G is then turned off to display data B on the liquid panel, a light source B is turned on after the liquid crystal responses completely, thereby forming one screen. However, the basic method of driving the backlight of FIG. 1 has a short turn-on time of the backlight due to an image data input and response time of the liquid crystal, which reduces the contrast. Therefore, to solve this problem, a drive method of using a scrolling backlight has been introduced.
FIG. 2 shows a drive method using a scrolling backlight of a field sequential display apparatus according to the related art.
Referring to FIG. 2, in the drive method using the scrolling backlight, a screen is divided into areas, and different light sources are used for each of the areas. Namely, a light source is first activated for an area where the liquid crystal responses completely, and other color light sources are activated for other areas. The drive method using the scrolling backlight can have a greater turn-on time of the light source than a basic drive method. However, in the scrolling backlight drive method, color purity may deteriorate due to a color mixture of light sources, since light sources of different colors are concurrently turned on for one screen. To solve this problem, a barrier rib (separating rib) may be placed between separately driven areas to prevent interference between light sources. However, if the barrier rib is used to prevent the color mixture, luminance may vary because the portion where the barrier rib is positioned receives less light than other portions.
In addition, in a field sequential drive method according to the prior art, if a moving white image is represented by a mixture of the three primary colors R, G, and B, color breakup occurs at the leading and trailing edges, since the R, G, and B colors are represented with a time difference as the picture moves.